Vuurmuur is a firewall manager for Linux that supports IPv4, IPv6, and traffic shaping. It has powerful monitoring features for logging and live connections. It can be managed entirely through an Ncurses GUI, on the console, or through SSH.

RackTables is a tool to manage tens of racks, hundreds of servers, and thousands of MAC and IP addresses. It will work with a single rack as well. It features a real-life rackspace model, typed rack objects with flexible attribute sets, a tagging system, IP address management ready for NAT, virtual routers and load balancers, accurate network connection handling, a universal search function, a multi-user access model, and an extensible dictionary.

Covert_qos uses the Quality of service fields in IPv4 and IPv6 to set up a unidirectional covert channel. In IPv4, this is a single byte per packet; in IPv6 it is a maximum of 3 bytes per packet. Files can be sent over the channel. It uses Linux netfilter queues as a basis.

smtp-cli is an SMTP command line client with support for advanced features such as STARTTLS, SMTP-AUTH, or IPv6. It also has scriptable message composition capabilities supporting anything from simple plain-text messages right up to building complex HTML emails with alternative plain-text part, attachments, and inline images. It's also a convenient tool for testing and debugging SMTP servers' setups. smtp-cli can be used to check a given server's capabilities, to test your server's setup, or to create and dispatch email messages. The command line interface is intuitive, and everything is scriptable and can run in a completely non-interactive mode from scripts or cron jobs. smtp-cli is ideal for shipping log files from remote machines, running periodic mail delivery test loops, etc.

Managed TFTP server is a TFTP server. The main TFTP class runs without modifications on Mono. It works both in IPv4 and IPv6 mode. It has correct retry behavior. It supports the following TFTP options: block size, transfer size, and timeout. It's possible to run in single port mode, which ensures that only port 69 will be used for TFTP transfers, simplifying firewall and router configuration. It supports many concurrent transfers. It runs as a Windows service. It supports multiple TFTP servers on different endpoints, each serving its own root directory. It has an advanced MSI-based installer. It logs to the windows event log. It has a permissive MIT license so it can be used in commercial projects.

Suricata is an Intrusion Detection and Prevention (IDS/IPS) engine developed by the Open Information Security Foundation and its supporting vendors. The engine is multi-threaded and has native IPv6 support, file extraction capabilities, and many more features. It's capable of loading existing Snort rules and signatures, and supports many frontends through Barnyard2.

ip2clue provides access to multiple databases (Maxmind, Software 77, Webhosting.info and ip2location) to retrieve country information associated with IP addresses. It has a daemon that supports lots of concurrent connections and a client binary. Some client examples are also provided in languages including PHP and C.